diff --git a/arrow-array/src/array/fixed_size_binary_array.rs b/arrow-array/src/array/fixed_size_binary_array.rs
index e8272be5d625..39bfc1db4ad1 100644
--- a/arrow-array/src/array/fixed_size_binary_array.rs
+++ b/arrow-array/src/array/fixed_size_binary_array.rs
@@ -643,6 +643,8 @@ unsafe impl Array for FixedSizeBinaryArray {
     }
 
     fn offset(&self) -> usize {
+        // Slices are normalized by slicing `value_data`/`nulls` directly;
+        // FSB does not retain a separate logical element offset.
         0
     }